Antifouling properties of different Plasma Electrolytic Oxidation coatings on 7075 aluminium alloy

In this work the antifouling properties of different Plasma Electrolytic Oxidation (PEO) coatings produced on samples of 7075 aluminum alloy were studied and compared with those of samples treated with more commercial treatments, such as traditional anodizing and painting, and untreated ones. After the treatments, the different samples were characterized through scanning electron microscope (SEM) observations. The antifouling tests were carried out immersing the different coated samples in the Piave river for a month, collecting one sample series every week. After the immersion test, to evaluate the colonization by microalgae, the samples were investigated through stereomicroscope, inverted light microscope, and SEM. Results showed that the addition of silver/copper particles in the electrolyte does not modify the PEO process, obtaining thick and adherent coatings that contain particles both inside and outside of the pores. As regards the antifouling properties, surface PEO treated with copper particles exhibited a good effect inhibiting the colonization by microalgae.